AS3687XM - Lighting Management Unit

Description

The AS3687XM is a highly-integrated CMOS Lighting Management Unit for mobile telephones, and other 1-cell Li+ or 3-cell NiMH powered devices.

The AS3687XM incorporates one Step Up DC/DC Converter for white backlight LEDs, one low noise Charge Pump for indicator- or RGB- LEDs, LED test circuit (production test of the soldered LEDs at the customer site), one Analog-to-Digital Converter, seven current sinks, a two wire serial interface, and control logic all onto a single device.

The AS3687XM has an audio input to control one or two RGB LEDs.

Output voltages and output currents are fully programmable.

Key Features

• High-efficiency step-up DC/DC converter
  • Up to 25V/50mA
  • Programmable output voltage
  • Overvoltage protection
• High-efficiency low-noise charge-pump
  • 1:1, 1:1.5 and 1:2 Mode
  • Automatic up switching
  • Output current up to 100mA
  • Efficiency up to 95%
  • Only 4 external capacitors required: 2 x 500nF Flying Capacitors, 2 x 1μF Input/Output Capacitors
  • Supports LCD white backlight or RGB LEDs
• Seven fully programmable current sinks
  • 8-bit from: 0.15mA to 38.5mA
  • Three current sinks hight voltage capable
  • Individual enable/disable
• Internal PWM Generation
  • 8 Bit resolution
  • Autonomous logarithmic up/down dimming
• LED pattern generator
  • Autonomous driving for RGB LEDs
  • Support indicator LEDs
• Audio can be used to drive RGB LED
  • RGB color and brightness is dependent on audio input amplitude
  • Can drive one or two RGB LEDs
• 10-bit successive approximation ADC
  • 27μs conversion time
  • Selectable inputs
• Internal temperature measurement
• Support for automatic LED testing (open/short)
• Standby LDO always on if serial interface is on
  • Regulated 2.5V max. output 10mA
  • 3μA Quiescent Current
• Automatic wakeup if serial interface is enabled (allows ultra low power for device shutdown)
• Wide Battery Supply Range: 3.0 to 5.5V
• Two Wire Serial Interface
• Overcurrent and Thermal Protection
• Smallest package WL-CSP
  • 2x2.5mm
  • 4x5 balls
  • 0.5mm pitch

Applications

• Smartphones
• Feature Phones
• Mobile Phones
• Portable DVD / TV Player
• Portable Learning Toys
• Portable Navigation Devices
• Portable Medical Consumer Devices

Block diagram for AS3687XM - Lighting Management Unit